Category: JavaScript Answers

Sometimes, we want to get full file path in Node.js.

In this article, we’ll look at how to get full file path in Node.js.

How to get full file path in Node.js?

To get full file path in Node.js, we use the path.resolve method.

For instance, we write

const path = require("path");
const absolutePath = path.resolve("./Uploads/MyFile.csv");

to call path.resolve with a relative path string to return the full path of the file as a string.

Conclusion

To get full file path in Node.js, we use the path.resolve method.

Sometimes, we want to convert an image to a base64-encoded data URL in server-side JavaScript.

In this article, we’ll look at how to convert an image to a base64-encoded data URL in server-side JavaScript.

How to convert an image to a base64-encoded data URL in server-side JavaScript?

To convert an image to a base64-encoded data URL in server-side JavaScript, we can use a Buffer.

For instance, we write

const fs = require("fs");

const base64Encode = (file) => {
  const bitmap = fs.readFileSync(file);
  return new Buffer(bitmap).toString("base64");
};

to define the base64Encode function.

In it, we call readFileSync to read the file.

Then we convert it to a buffer with Buffer.

And then we convert it to a base64 string with toString.

Conclusion

To convert an image to a base64-encoded data URL in server-side JavaScript, we can use a Buffer.

Sometimes, we want to add validation using Yup to check string or number length with JavaScript.

In this article, we’ll look at how to add validation using Yup to check string or number length with JavaScript.

How to add validation using Yup to check string or number length with JavaScript?

To add validation using Yup to check string or number length with JavaScript, we call the test method.

For instance, we write

yup
  .string()
  .test("len", "Must be exactly 5 characters", (val) => val.length === 5);

to call test with 'len', an validation error string, and a callback to do the validation.

We check that the val has length 5 with (val) => val.length === 5.

Conclusion

To add validation using Yup to check string or number length with JavaScript, we call the test method.

Sometimes, we want to create a simple 10 second countdown with JavaScript.

In this article, we’ll look at how to create a simple 10 second countdown with JavaScript.

How to create a simple 10 second countdown with JavaScript?

To create a simple 10 second countdown with JavaScript, we use the setInterval method.

For instance, we write

<progress value="0" max="10" id="progressBar"></progress>

to add a progress element.

Then we update it by writing

let timeleft = 10;
const downloadTimer = setInterval(() => {
  if (timeleft <= 0) {
    clearInterval(downloadTimer);
  }
  document.getElementById("progressBar").value = 10 - timeleft;
  timeleft -= 1;
}, 1000);

to call setInterval with a function that calls clearInterval to stop the timer if timeLeft is 0 or less.

Otherwise, we update the progress element with the value of 10 - timeleft to show the count down value.

And then we decrement timeLeft by 1.

Conclusion

To create a simple 10 second countdown with JavaScript, we use the setInterval method.

Sometimes, we want to add a custom button to the toolbar that calls a JavaScript function with CKEditor.

In this article, we’ll look at how to add a custom button to the toolbar that calls a JavaScript function with CKEditor.

How to add a custom button to the toolbar that calls a JavaScript function with CKEditor?

To add a custom button to the toolbar that calls a JavaScript function with CKEditor, we call the addCommand and addButton methods.

For instance, we write

<textarea id="container"></textarea>

to add a text area.

Then we write

const editor = CKEDITOR.replace("container");

editor.addCommand("mySimpleCommand", {
  exec(edt) {
    alert(edt.getData());
  },
});

editor.ui.addButton("SuperButton", {
  label: "Click me",
  command: "mySimpleCommand",
  toolbar: "insert",
  icon: "https://avatars1.githubusercontent.com/u/5500999?v=2&s=16",
});

to convert the text area to a rich text editor with CKEDITOR.replace.

Then we call addCommand to add a command that calls alert.

Then we call addButton to add a button that issues the mySimpleCommand command.

Conclusion

To add a custom button to the toolbar that calls a JavaScript function with CKEditor, we call the addCommand and addButton methods.